1. Field of the Invention
The present invention relates to a mounting structure of filter for cooler of construction machine detachably mounted on the front surface side of the cooler such as radiator.
2. Description of the Related Art
In a hydraulic excavator, a working attachment (not shown) is mounted in a front section of an upper rotating body 2 disposed rotatably around a vertical shaft on a crawler type lower traveling body 1 shown in FIGS. 8 and 9.
As shown in FIG. 9, an engine 4 is installed in the left and right direction (width direction) of the upper rotating body 2 in an engine room 3 in a rear section of the upper rotating body 2.
On the right side of the engine 4 (the right side seen from the rear side of the upper rotating body 2, the same is applied to the direction of the left and right below), is provided a hydraulic pump 5 driven by the engine 4, and on the left side thereof, is provided a cooler 6.
The cooler 6 is formed of a plurality of heat exchangers such as a radiator for cooling the engine, an oil cooler for cooling working oil and an intercooler for a turbocharger. Here, for the sake of convenience, the cooler 6 is shown as a single unit.
By rotation of a cooling fan 7 provided between the cooler 6 and the engine 4, the outside air is sucked in from a suction opening (not shown) in an external body (usually called as a guard) for forming the engine room 3 and passes through the cooler 6 as the cooling air.
The upper surface side of the external body is formed of a hood 8 (refer to FIG. 8) provided with a bonnet, and a back surface and a side surface thereof are formed of a counterweight 9.
Maintenance ports 10 and 11 from the exterior on both the left and right sides of the counterweight 9 are opened and closed by maintenance panels 12 and 13. It should be noted that hinges 14 are centers for opening and closing the panels 12 and 13.
To a tip of a duct 15 for bringing the sucked air to the cooler 6 on the front surface side of the cooler 6 (the side of a surface opposing to a flow of the sucked air, that is, a surface on the left side of the upper rotating body 2), is detachably mounted a filter 16.
A portion of mounting the filter is enlarged and shown in FIGS. 10 and 11.
For the sake of convenience of treatment or the like, the filter 16 is divided into two as in FIG. 11, and both upper and lower filters 17 and 18 are mounted to the tip of the duct in a state of being in contact with each other on the upper and lower sides respectively.
In a peripheral edge of the tip of the duct, is provided a filter mounting portion 19 provided with a filter abutment surface 19a facing towards the upstream side of the air flow. A peripheral edge part of the filter 16 is fitted into the mounting portion 19 in a state of being brought into abutment with the abutment surface 19a. 
Specifically, an upper end part and both front and rear end parts of the upper filter 17 (both front and rear end parts in the case of following the direction of the upper rotating body 2, that is, both left and right end parts seen from the upstream side of the air flow) are mounted to the filter mounting portion 19, and a lower end part and both front and rear end parts of the lower filter 18 are mounted to the filter mounting portion 19.
It should be noted that precisely speaking, in the filter 16 (the upper and lower filters 17 and 18), a filter frame is mounted to a circumference of a filter main body. There is sometimes a case where the filter 16 is directly mounted on the front surface side of the cooler 6 without the duct 15. Further, there is sometimes a case where the filter 16 is formed as a single filter.
The above configuration is disclosed in Japanese Patent Laid-Open Nos. 2006-52689 and 2001-342645.
Since maintenance is highly frequently required for the filter 16, the filter 16 is detachably mounted to the filter mounting portion 19.
Conventionally, as mounting means, a fastening tool such as a butterfly bolt and a pin is used for the peripheral edge part of the filter 16 (an upper part and both the front and rear sides of the upper filter 17 and a lower part and both the front and rear sides of the lower filter 18).
In such a case, attachment and detachment of the filter 16 are more desirably performed through the left maintenance port 10 from the ground by opening the left maintenance panel 12 as in FIG. 9 than performed from the upper surface side of the engine room by getting on the hood 8 in terms of operating efficiency and safety.
However, a filter attachment and detachment operation such as fastening-back of the fastening tool, inserting and taking-out of the pin and positioning at the time of mounting is troublesome, and there is a fear that the fastening tool is lost.
Further, since the front end side of the filter which is the inner side seen from the maintenance port 10 is not easily touched and accessed, an operation of the fastening tool is further troublesome and a work is hard.
Therefore, work efficiency at the time of attaching and detaching the filter is deteriorated and maintenance property is degraded.